Vaccine safety

All vaccines approved for use in New Zealand have a good safety record and have ongoing safety monitoring.

Immunisation: Common Questions Answered

Immunisation is one of the best ways to protect your child against the risk of serious diseases. If you’re concerned about immunisation, knowing the facts can help you feel more confident about immunising your child.

Immunisation: Common Questions Answered.

Chapter 1/10 Why immunise?

[Doctor Keriana Bird in her office to camera]

Dr Bird: Kia Ora, I'm Dr Kiriana Bird. I'm a doctor in the Hawke's Bay, and I'm also a mum.

As parents, we do everything we can to protect the health and wellbeing of our tamariki.

[We see Dr Bird opening door to her office and talking to camera before sitting down at her desk.]

Immunisation is one of the best ways for us to help protect our babies and children against serious, preventable diseases.

Dr Bird: Every day, our bodies fight infection using a natural immune response.

Immunisation uses the same natural immune response to protect against serious diseases – some of which can be deadly.

The National Immunisation Schedule is a series of free immunisations for our tamariki at different stages of their lives. It protects our tamariki, whānau and community against the spread of serious, infectious diseases; from before a baby is born right throughout their lives.

[The National Immunisation schedule appears on screen and the different milestones transition on screen in order from pregnancy to 65+ years. Following this, all the diseases that immunisation protects against appear.]

Immunisation is one of the best ways to prevent infectious diseases, such as measles, tetanus and whooping cough and even some kinds of cancer.

[Cuts back to Dr Bird] This is why the Ministry of Health and health organisations around the world support immunisation.

Chapter 2/10: Common questions answered

Dr Bird: In New Zealand, more than 90 percent of babies are fully immunised on time. But working in a General Practice, we sometimes meet parents who are concerned about immunisation.

It’s natural for parents to worry whether they’re doing the best thing for their kids, so I’m here to help answer some of the most common questions, like what’s in a vaccine and what are their potential risks and side effects?

Let’s meet some families, who like you, have questions about immunisation…

Chapter 3/10: How safe are vaccines?

[We see Erika and her family playing outside]

Erika: How safe are vaccines?

[Erika and her husband sitting at table with their young child]

Dr Bird: Extremely safe. Before any vaccine is approved for use, it goes through a long testing process by scientists around the world and in New Zealand to ensure it’s safe and effective for our tamariki.

[Dr Bird talking to camera.]

This process can take several years and compares the health of people who have been immunised with those who haven’t. And safety doesn’t stop there.

[Cuts to scientist working and looking at their computer screen.]

Safety is also continuously monitored for the life of the vaccine to ensure it remains safe.

[Cuts back to Dr Bird.]

As part of this process, the Centre for Adverse Reactions Monitoring at Otago University, records reactions reported after vaccinations so that scientists can keep track of any reactions that may occur.

[Centre for Adverse Reactions Monitory (CARM)]

Chapter 4/10: Are there any side effects from vaccines?

[Erika and her husband sitting at table with their young child]

Erika: Are there any side effects from vaccines?

Dr Bird: Vaccines are a form of medicine, and all medicines have some side effects, even commonly used ones like paracetamol. With immunisation, vaccines often cause a mild reaction, and rarely causes a more serious problem.

[Dr Bird talking directly to camera.]

For example, your child may experience a mild reaction to the vaccine such as a slight fever or redness at the injection site – this is the immune system’s natural response to the vaccine, and it usually doesn’t last very long.

[Supporting GFXs on half screen.]

When they have fevers, some babies experience a brief seizure. Sometimes this can be caused by a vaccine. And while this may be scary, it doesn’t cause any permanent harm and babies recover quickly.

About one in every million people who are vaccinated will experience a severe allergic reaction, called anaphylaxis.

This is why you’re asked to wait for 20 minutes after your child’s immunisation so that trained nurses can immediately treat your child if they have an allergic reaction. Treatment is very fast and effective.

[Animation/infographic to support the ‘1 in 1 million’ statistic mentioned in the VOICEOVER.

These allergic reactions are more commonly caused by some foods, bee stings and other medication.

[Dr Bird talking to directly to camera]

There are a couple of vaccines that have their own rare but particular reactions – you can find out more from carefully researched sites like Immunisation Advisory Centre or Medsafe, but most importantly you can talk through any worries that you may have with your local nurse or GP.

[GFX: Immunisation Advisory Centre]

There are lots of common myths about immunisation that parents may worry about, even though these have been proven to be false through extensive research. Many studies show that vaccines do not cause autism, miscarriage, sudden infant death or a number of other health conditions.

[Supporting GFX on half screen]

Chapter 5/10: Is there a natural alternative to immunisation?

[Footage of Josie and Jo in their kitchen preparing some food.]

Josie: Is there a natural alternative to immunisation?

[Dr Bird talking directly to camera.]

Dr Bird: I can understand you want the best start for your little one.

Your body has a natural immune system that fights infections. Clean water, fresh air, exercise and healthy eating all help to keep you well.

But some diseases move too fast for even a healthy immune system to fight off. This can cause damage to the body that can take a long time to heal. The only way to protect against these diseases is to immunise.

Immunisation uses the body’s natural immune response, by preparing your baby’s immune system to identify and fight off diseases without the unnecessary risk of your baby getting sick.

As a doctor, I’ve seen what happens when kids get really sick. For me, prevention is always better than treatment.

Chapter6/10: A lot of these diseases aren’t around anymore. Do we still need to worry?

Josie and Jo at table and Josie talking directly to camera.

Josie: A lot of these diseases aren’t around anymore. Do we still need to worry?

Dr Bird: I guess vaccines have become a victim of their own success in that way. Some diseases are less common now but your grandparents might remember the harm they caused to our communities. ,/p>

[Dr Bird talking directly to camera]

Thanks to immunisation, we’re lucky that a lot of diseases are no longer common in our communities – but they’re still around and many are just a plane ride away. When most people are immunised, the threat of these diseases becomes less. But if too many people aren’t immunised then these diseases can spread easily and quickly.

In New Zealand in recent years, we’ve had outbreaks of measles, mumps and whooping cough affecting thousands of people, with hundreds of babies needing hospital treatment.

[Footage of people walking down the street.]

[Images of relevant newspaper clippings transitioning on screen.]

So although some diseases, like polio are now rare, they can still be brought into New Zealand by people who have travelled overseas. This is why it’s important to immunise so that together, we can prevent the risk of infectious diseases in our communities.

[Dr Bird talking directly to camera

Chapter 7/10: I’ve heard some people still get sick.

[We see footage of Tracy and her whanau playing with their baby happily.]

Tracy: I’ve heard some people still get sick – does that mean immunisation doesn’t always work?

[Cuts to Tracy and her partner on couch, Tracy talking directly to camera.]

Dr Bird: Vaccines usually stop someone from getting a disease, but not in every case. Immunisation is still one of the best things we can do to help protect our whānau.

[Dr Bird talking directly to camera.]

Immunisation significantly reduces your chance of catching a disease - and for some vaccines by up to 98 percent. But if you’re immunised and still catch the disease, you’re less likely to get seriously ill, or need to go to hospital.

For a very few people, their immune systems don’t respond to immunisation. So the best way to protect them is to make sure everyone around them is immunised.

Chapter 8/10: What ingredients are in a vaccine?

Tracy: I saw something on Facebook about vaccines being toxic – are they going to be ok for my baby?

[Cuts to Tracy and her partner on couch, Tracy talking directly to camera.]

Dr Bird: There are lots of stories on the internet about vaccine ingredients that are worrying, but misleading. Vaccines are mostly water and a weakened or small part of the germ they protect against.

[Dr Bird talking directly to camera]

They have a few other ingredients to make sure the vaccine works properly and stays fresh. These ingredients are in tiny amounts, and are common in food, medicines or already in our bodies.

[Supporting GFX on half screen.]

One ingredient you might have heard of is formaldehyde. It’s used in the production of some vaccines to kill the germ so that we don’t catch the actual disease. It’s in tiny traces and the amount is usually too small to even measure. Our bodies already produce small amounts of formaldehyde, but actually, there’s far more in a pear than in a vaccine. So even children’s bodies are more than capable of dealing with these tiny amounts.

[Supporting GFX on screen illustrating the amount of formaldehyde in a pear.]

[Cuts back to Dr Bird.]

Aluminium is also used in some vaccines to help our immune system respond to a vaccine. Aluminium is the 3rd most common element in the world – we find it in the things we eat and drink every day but our bodies are good at removing it.

Because vaccines contain such tiny amounts of each ingredient, they’re not harmful or toxic for our little ones.

[Cuts to 3 dishes being put on table showing the different amounts of aluminium in breastmilk, childhood vaccine and the minimum risk level. Supporting graphically.]

[Cuts back to Dr Bird.]

Strict guidelines and ongoing monitoring of vaccines make sure they’re safe.

All medicines have benefits and risks. With immunisation, the benefits significantly outweigh the risks. When we don’t have personal experience of those diseases it can be hard to see these benefits. Our job is to help you make an informed choice for your whānau.

Chapter 9/10: An informed choice

[Footage of Maori family in nurse's office being talked to with nurse.]

VOICEOVER: Being informed about immunisation will help you understand the advantages of immunising your whānau, and any risks associated with a vaccine or a serious disease.

There’s a lot of information about immunisation which can be confusing. So to make the best decision for your whānau, it’s important to get trusted information from reliable sources.

To help you make an informed decision, think about whether the information is up to date and relates to New Zealand. Check that it's based on sound evidence, backed up by clinical studies and ongoing monitoring. And that it's supported by health professionals and scientific organisations.

[Supporting GFX on half screen.

Chapter 10/10 worldwide protection

[Footage of Maori family in their home playing happily with young baby. We see the grandmother bring the baby to her chest gently.]

Voiceover: Every country in the world uses immunisation to protect against the spread of diseases. Worldwide millions of lives have been saved by these immunisation programmes.

[Cuts to footage of globe illustrating all the countries in the world that are protected by immunisation.]

Voiceover: Although New Zealand’s immunisation programme has a lot in common with other countries around the world our programme is designed to meet the needs of our tāngata.

[Cuts to footage of children in playground.]

Voiceover: In Aotearoa, we decide which immunisations to include based on the diseases we want to protect our whānau against.

Dr Bird: The benefits of immunisation are huge – it reduces deaths, hospitalisations, permanent health damage and serious illness. But as with all medicine, there is a risk of discomfort or a short term reaction, and a very small chance of a vaccine causing a more serious reaction.

Because of this, it’s easy to understand why immunisation may make parents feel nervous, and why it’s important to talk about these concerns with a health professional.

Immunisation is one of the best ways to help protect your child against the risk of serious diseases and protect our whole community.

Make the choice to immunise your child and give them the best start to a healthy future.

Voiceover: Protect your whānau. Immunise. It’s their best protection.

[Cuts to end screen.]

[Protect your whanau. Immunise, it’s their best protection.]

[Ministry of Health, HPA and Immunise their best protection logo lock.]

[Transitions to details about more information.]

View the full version of this video: Immunisation: Common Questions Answered.

All medicines have risks, including vaccines.  However, the risk of catching serious illnesses is far greater than the risks of vaccination. For more information about the risk of disease compared with vaccination, see our publication Childhood Immunisation and the Immunisation Advisory Centre’s Comparison of possible disease complications and vaccine responses.

Safe development and manufacturing

Strict procedures are followed when vaccines are made. Before a vaccine can be approved for use it goes through a long testing process by international scientists to check that it is safe, and that it works. This process usually takes several years and includes trials on people who volunteer to use it. Before a vaccine is approved for supply in New Zealand the manufacturer must demonstrate its quality, that it works well and that it is safe to the satisfaction of Medsafe, a division of the Ministry of Health.

Medsafe’s evaluation is performed to internationally defined standards and is based on data from clinical trials.

The gold standard for clinical trials includes three phases:

  • Phase 1: Small numbers of people take the same vaccine using different methods of delivery and/or dosage. Assesses safety and immune response.
  • Phase 2: Uses larger numbers of people and compares new treatments with a placebo. Continues to assess safety and immune response.
  • Phase 3: Large, randomised trial(s) to test the effect of a new vaccine against a control group. This phase tests safety and efficacy, which is the percentage of people that the vaccine protects from catching the disease.

Ongoing monitoring

Once a vaccine has been introduced to New Zealand, the Centre for Adverse Reactions Monitoring (CARM) at Otago University records reactions reported after vaccination.

Vaccinators are asked to report all clinically significant events following vaccination to CARM. Parents may also report online or by ringing CARM on 03 479 7247. The information provided to CARM by doctors, nurses and parents will assist in identifying those children who should receive follow-up immunisation in a controlled environment, such as a hospital.

Medsafe reviews reports about adverse events from all medicines, and if they detect a safety concern, they can provide updated advice to health professionals about the safe use of the medicine, restrict its use or in rare circumstances recall a medicine. For more information about this process see Medicines Safety Monitoring.

Any serious reactions may also be recorded on the National Immunisation Register (NIR).

Parents should contact their doctor or Healthline (phone 0800 611 116) if they are worried about their child following immunisation.

Vaccine ingredients

Vaccines include antigens (weakened or killed germs, or parts of germs) which help your body recognise and fight off disease. They also include other ingredients to help the vaccine work and keep it fresh. Some ingredients are used during manufacture to grow or kill the germs, but almost all of these are removed from the final product and only trace amounts remain. The ingredients for each vaccine in the National Immunisation Schedule are set out in Data Sheets published by Medsafe. There is a useful PDF guide to vaccine ingredients and how they work called 'Vaccine ingredients' under on the Immunisation Advisory Centre resources page.

Pear, salt shaker, bottled water, icecream, baby shampoo
Vaccine ingredients are also found in these common household products

Vaccine administration

Everyone who is able to administer vaccines in New Zealand has undergone specialised training, whether they are practice nurses, general practitioners, midwives or pharmacists. Training ensures that vaccinators can provide emergency treatment, handle vaccines safely and effectively, and communicate accurately and effectively with patients to gain informed consent. 

Vaccine administration errors occur rarely, for example where one vaccine is mistakenly given in place of another, or an additional dose of a vaccine is given. These do not usually cause any harm to patients, but are taken very seriously and reported to CARM. The Health and Disability Commissioner can investigate complaints about administration errors. Changes to vaccination processes, resources or packaging are made when problems are identified, to reduce the chance of future administration errors.

All vaccines in use in New Zealand come in single-dose vials, except for the Bacillus Calmette-Guerin (BCG) vaccine, which is given to at-risk children to protect against tuberculosis, and comes in 10-dose vials.  BCG vaccinators receive special training to administer this vaccine. 

For detailed information about vaccinator training, see the Immunisation Handbook and Immunisation Advisory Centre website

Vaccine storage

Most vaccines must be stored and transported at a constant temperature of between 2 and 8 degrees Celsius to ensure they remain safe and effective. Immunisation providers must store vaccines in a pharmaceutical fridge, with two systems of recording temperatures. The process for tracking storage temperature is called the cold chain. Temperatures are checked and logged regularly so that any vaccines stored outside the recommended temperature are identified before they can be administered to patients. Cold chain processes are regularly checked and audited.

For detailed information about cold chain processes, see National Immunisation Programme cold chain management.

Further information

For more information about the safety and effectiveness of immunisation, and how common and severe the diseases it protects against are, the Immunisation Handbook and the following resources are useful.


National Centre for Immunisation Research and Surveillance, Australia

Centre for Disease Control and Prevention, USA

American Academy of Pediatrics

Institute for Environmental and Scientific Research (ESR)

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